U.S. Pat. No. 4,422,887 to Spitzer et al discloses aerosol synthetic polymer--liquefied propellant compositions which when expelled from an aerosol container form cold pad polymeric foamed structures whose temperature is initially at least 30.degree. C. below the ambient temperature at which the cold formed structure is formed, said formed structures containing open and/or closed cells which may contain an additive which is deposited in the pores and/or walls of the foamed structure as the foamed structure is formed. The aforedescribed prior art aerosol compositions when expelled on a surface exert a pronounced cooling effect on said surface until the propellant component thereof is completely evaporated.
The essential ingredients of the aerosol compositions of the above-mentioned U.S. Pat. No. 4,422,887 are:
a. a film-forming synthetic polymer in an amount within the range from about 2% to about 30% by weight of the composition; PA1 b. at least one liquefied propellant boiling below -10.degree. C.; PA1 c. the total propellant being in an amount within the range from about 50% to about 90% by weight of the composition; and having a heat vaporization of at least 55 calories per gram; the propellant being capable of dissolving the synthetic polymer at least in the presence of a co-solvent that is soluble in the propellant and in solutions of the synthetic polymer in the propellant at ambient temperature; and PA1 d. at least one nonsolvent that is soluble in the propellant but in which the synthetic polymer is insoluble in an amount within the range from about 1% to about 85% by weight of the composition; PA1 the composition forming on volatilization of propellant at ambient temperature a coherent formed structure containing open and/or closed cells, and having a temperature at least 30.degree. C. below ambient temperature. PA1 (a) from about 10 to about 60 percent by weight of an ointment that contains an oil phase and may contain an aqueous phase in the form of an emulsion, where the oil phase of the ointment does not flow below about 35.degree. C., in PA1 (b) about 40 to about 90 percent by weight of a liquefied propellant that is at least 80 percent non-polar propellant in an aerosol container, whereby a solid or semi-solid deposit is formed when a portion of the composition is expelled and this deposit placed in contact with injured tissue it provides instant relief from pain and itching as the result of its sustained cold, thereby enhancing the performance of the ointment with its slower action medications.